The present invention pertains to valve inspection, and more particularly, to an in-line inspection technique that provides a simple, non-intrusive verification of check valve operability without valve disassembly.
Conventionally, in process industries such as power plants and the like, the operability of check valves is verified during planned outages, by disassembling the valve, inspecting the valve components, and then reassembling the valve. Particularly in nuclear power plants, this conventional procedure has many disadvantages. The major disadvantage is that the valve to be inspected is itself often radioactive, or it contains residues of radioactive fluid. The typical time required for conventional verification is on the order of several hours, during which the maintenance worker may be exposed to, or must be protected from, radiation. In addition, there exists some risk that the valve will not be correctly reassembled, which could adversely affect valve performance.
Thus, the need exists for a reliable, non-intrusive, in-line check valve inspection technique for verifying valve operability.